Bernese Oberland
Gadmertal
Widespread danger. Deteriorating: moderate this morning, considerable by afternoon, with wind slab and wet snow at the surface — turn round before it gets there.
Day Risk Profile
Avalanche Problems
Wind slab
2-
Field notes
Look for fresh snow deposits on Slope facing downwind/ wind sheltered aspect. Snow deposits can attain several times average snow depth.EAWS glossary, in Usually a steep, elongated, eroded trench; typically prone to snowdrift accumulation.EAWS glossary and Rounded or elongated concavity; typically tending to accumulate snowdrift.EAWS glossary, and behind ridgelines and abrupt changes in terrain — these are where the wind has loaded the snow into slabs that are easy to trigger. Recent avalanches, shooting cracks under your weight, and Distinctive noise (resembling a “whumpf” sound) occurring when a weak layer beneath a slab collapses. The air of the weak layer is forced outside the snowpack, with the resulting whumpf sound being heard. The sound usually indicates an unstable situation and can be accompanied by surface cracking. A whumpf is a clear avalanche alert.EAWS glossary sounds are clear confirmations of the problem. The safest move is to avoid wind-loaded terrain entirely. NB wind signs alone don't always mean an avalanche problem exists, and the age of drifted snow is hard to judge.
Wet snow
3
Field notes
Rolling snowballs, deep penetration when you step or ski, and small natural slides are clear signals that the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is losing strength. After a clear, cold night the surface often freezes into a strong supporting Layer of hard-compacted snow resulting from a melt-freeze process or wind.EAWS glossary, and conditions are favourable in the early morning. After a warm, overcast night, the problem may be present from the start of the day. Plan early returns and watch the runout zones below you.
Snowpack & Weather
Snowpack
With the mild weather, partly overcast nights and rain in places, moistening of the Snow deposited on the ground in a multiplicity of layers.EAWS glossary continued over the course of the last week. On south-facing slopes, the snowpack is water-saturated up to around 3000 m, and on east- and west-facing slopes up to 2500 to 2700 m, while on north-facing slopes it is water-saturated below 2000 m, with moistening progressing between 2000 and 2400 m.
In the south, fresh and drifted snow at high altitudes is in some places still prone to triggering, especially on shady slopes. Avalanches can also in some cases still be triggered by human activity in faceted Snowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. Typical crystals in dry weak layers causing avalanches are : precipitation particles; surface hoar; faceted crystals; hollow crystals; graupel. Generally >1mm in size, loose grains with few bonds Wet weak layers can be formed by all snow crystal/grain types.EAWS glossary in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary. Such Locations delineated by aspect or altitude where avalanches can trigger and people or objects are at risk.EAWS glossary are generally located at altitudes where the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is becoming moist for the first time. In central Valais and in Grisons in particular, such avalanches can in some cases sweep away the entire snowpack, especially on slopes with light snow cover.
Weather review for Tuesday
Overnight to Tuesday, skies were often cloudy with some widespread precipitation. In the north, the snowfall level fell from 1800 m down to 1500 m, while in the south it was around 2000 m. It was very sunny over the course of the day on the southern flank of the Alps and in Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary in the west, but often cloudy elsewhere.
Fresh snow
From Monday afternoon to Tuesday afternoon above approximately 2400 m:
- main Alpine ridge in Upper Valais, western Ticino: 10 to 20 cm
- elsewhere a widespread few centimetres
Temperature
At midday at 2000 m, around +4 °C in the west and south and 0 °C in the northeast
Wind
Light to moderate southerly during the night, backing northeasterly during the day
Weather forecast to Wednesday
Overnight to Wednesday, there will be broken cloud in Grisons, with skies often clear elsewhere. It will be very sunny during the day. There is a possibility of isolated showers in the afternoon in the far south.
Fresh snow
-
Temperature
At midday at 2000 m, around +5 °C
Wind
Light from variable directions
Outlook to Friday
Skies will only occasionally be clear overnight to Thursday. During the day, it will be mostly sunny in Valais and in the south with sunny intervals elsewhere. After a mostly clear night, it will be very sunny during the day on Friday. The wind will be light from variable directions on both days. The zero-degree level will remain between 2600 m and 3000 m during the day.
The danger of dry avalanches will continue to decrease. The danger of wet avalanches will increase over the course of each day. Off-piste skiing and hut ascents should be completed in good time.